CN110962485A

CN110962485A - Recording method, recording apparatus and recorded matter

Info

Publication number: CN110962485A
Application number: CN201910923509.6A
Authority: CN
Inventors: 田中考利; 饭田贤一; 荒木和彦; 斯波哲史
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2018-09-28
Filing date: 2019-09-27
Publication date: 2020-04-07
Anticipated expiration: 2039-09-27
Also published as: EP3628504B1; US11123995B2; US20200101757A1; CN110962485B; EP3628504A1

Abstract

The invention relates to a recording method, a recording apparatus and a recorded matter. A recording method comprising a step of applying a first ink to a recording medium; and by applyingAnd a step of applying the second ink so that the second ink at least partially overlaps the area to which the first ink is applied to record an image on the recording medium. The first ink is an aqueous ink containing silver particles. The second ink is an aqueous ink containing a coloring material. The recording medium has an ink-receiving layer containing a halide ion selected from the group consisting of bromide ions and iodide ions. The ink-receiving layer had a thickness of 0.1mmol/m²Above and 0.8mmol/m²The following contents of halide ions.

Description

Recording method, recording apparatus and recorded matter

Technical Field

The invention relates to a recording method, a recording apparatus and a recorded matter.

Background

Inks containing metal particles have been used to form circuits by utilizing the conductivity of the metal particles used; however, in recent years, such inks are increasingly used for applications such as christmas greeting cards that exhibit a metallic feel. In particular, it has been required to impart a color tone to an image having a metallic feeling, in other words, to record a "color metallic image". Japanese patent laid-open No.2015-193126 proposes a method of recording a color metal image by applying a treatment agent containing inorganic particles to a recording medium having an ink-receiving layer formed thereon in advance, and then sequentially applying an aqueous ink containing silver particles and an aqueous ink containing a pigment.

The inventors of the present invention recorded a color metal image by the ink jet recording method described in japanese patent laid-open No.2015-193126 and studied the obtained image. As a result, it was found that the hue of the pigment ink is not easily recognized from the image and there are cases where the color developability is insufficient or the metallic feeling is lost due to the reduction in glossiness upon storage of the image.

Accordingly, the present invention provides a recording method and a recording apparatus that can record a color metal image having excellent color developability and excellent glossiness even after the image is stored. In addition, the present invention provides a color metallic recorded matter (color metallic recorded matter) having excellent color developability and excellent glossiness even after image storage.

Disclosure of Invention

The recording method according to the present invention comprises the steps of: a step of applying the first ink to the recording medium, and a step of recording an image on the recording medium by applying the second ink so that the second ink at least partially overlaps with the area to which the first ink is applied. The first ink is an aqueous ink containing silver particles. The second ink is an aqueous ink containing a coloring material. The recording medium has a composition comprising a compound selected from the group consisting of bromide ions and iodide ionsAn ink-receiving layer of halide ions of the group consisting of ions and a content (mmol/m) of the halide ions in the ink-receiving layer²) Is 0.1mmol/m²Above and 0.8mmol/m²The following.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

Drawings

Fig. 1A is a schematic perspective view of a relevant part of an example of a recording apparatus used in the inkjet recording method of the present invention.

Fig. 1B is a perspective view of the head cartridge.

Detailed Description

The present invention will now be described in further detail by means of preferred embodiments. In the present invention, the aqueous ink may be simply referred to as "ink". The physical property values are values at ordinary temperature (25 ℃ C.), unless otherwise specified.

The inventors of the present invention investigated the reasons for insufficient color developability and insufficient glossiness after storage with respect to an image obtained by the inkjet recording method described in japanese patent laid-open No. 2015-193126. A general recording medium having an ink receiving layer uses a cationic compound to improve water resistance and the like of a recorded image. The cationic compound is usually used in the form of a hydrochloride. Thus, the ink-receiving layer contains chloride ions. The inventors of the present invention have studied to find that, when the chloride ion content is low in the ink-receiving layer, an image in which the hue of the applied ink after the application of the ink containing silver particles can be easily recognized cannot be obtained. Hereinafter, in the present specification, a metal image in which the color tone of the ink containing the coloring material is recognizable is referred to as an image having "color developability".

First, an ink containing silver particles and an ink containing a coloring material are applied one on another in this order to a recording medium having an ink-receiving layer low in chloride ion content to record an image. Analysis of the obtained image revealed that a uniform silver layer could not be formed since most of the silver particles were not fused with the surrounding silver particles, and thus, the coloring material was not left on the silver layer. The reason is presumed to be as follows. When the ink containing the coloring material is applied in a state in which the silver particles are not fused, the silver particles are dispersed and moved into the liquid component of the ink containing the coloring material. The silver layer in this state does not leave the coloring material, and thus, color developability cannot be exhibited.

In order to solve the above-described problems, an ink containing silver particles and an ink containing a coloring material are applied one on another in this order to a recording medium having an ink-receiving layer high in chloride ion content to record an image. Analysis of the obtained image found that a silver layer was formed in a state in which most of the silver particles were fused with the surrounding silver particles and the coloring material remained on the silver layer. The reason is presumed to be as follows. When sufficient chloride ions are present in the ink-receiving layer, some of the ionized silver ions and chloride ions in the silver particles react with each other to form silver chloride. The silver chloride thus formed serves as a nucleus to promote the fusion of the silver particles and thus form a uniform silver layer. Unlike the above case, even when the ink containing the coloring material is applied to the silver layer in a state in which the silver particles are fused, the silver particles are hardly dispersed in the liquid component of the ink containing the coloring material. It is considered that due to this state of the silver layer, the coloring material may be left, and the color developability is exhibited.

However, according to the studies of the inventors of the present invention, it was found that when an image recorded on a recording medium having an ink receiving layer with a high chloride ion content is stored, glossiness gradually decreases with the passage of time, whereby metallic feeling is lost. The reason is presumed to be as follows. When the image is exposed to an oxidizing gas such as nitrogen oxide or to light, the silver atoms that make up the silver layer are activated and converted to silver ions. The silver ions thus generated react with chloride ions to generate silver chloride. In this way, silver chloride is gradually generated while the image is stored, and when silver chloride is generated in an amount more than necessary to maintain the fusion of silver particles, whitening and discoloration occur due to the silver chloride, resulting in a decrease in glossiness of the image.

In other words, although the chloride ion can cause the color metallic image to exhibit color developability as long as the chloride ion content in the ink-receiving layer is high, the chloride ion is a factor that reduces glossiness. Thus, in order to achieve both color developability and suppression of reduction in gloss after storage, it is necessary to promote fusion of silver particles even if the chloride ion content is low in the ink-receiving layer. Under this presumption, the inventors of the present invention have made studies and found that a specific amount of halide ions selected from the group consisting of bromide ions and iodide ions can be contained in the ink-receiving layer.

The effectiveness of bromide and iodide ions is illustrated by the solubility product of silver halide. Solubility product K_spThe product of the cation concentration and the anion concentration in the saturated aqueous solution of the insoluble substance. When the product of the ion concentration is greater than the solubility product K_spIn this case, silver halide precipitates. The solubility product at 25 ℃ for each silver halide is as follows. The following solubility product indicates that when a specific amount of silver ion is present, less bromide or iodide ion is required to generate the same amount of silver halide as compared to chloride ion.

Solubility product of silver chloride 1.6 × 10^-10(mol/L)²

Silver bromide solubility product 4.0 × 10^-13(mol/L)²

Solubility product of silver iodide 8.5 × 10^-17(mol/L)²

In the present invention, a recording medium having an ink-receiving layer containing halide ions selected from the group consisting of bromide ions and iodide ions, which require a smaller amount to generate silver halide, is used. In addition, the halide ion content (mmol/m)²) It is required to be 0.1mmol/m²Above and 0.8mmol/m²The following. When the content of halide ions is less than 0.1mmol/m²When the amount of halide ions is too small, the fusion of silver particles is not promoted and the image does not exhibit color developability. Meanwhile, when the content of halide ions is more than 0.8mmol/m²In the case where the amount of halide ions is too large, crystals of silver halide are excessively generated during image storage, resulting in whitening and discoloration, and thus, reduction in glossiness after image storage cannot be suppressed.

Recording method and recording apparatus

In the recording method of the present invention, a first ink which is an aqueous ink containing silver particles, a second ink which is an aqueous ink containing a coloring material, and a recording medium in which an ink receiving layer containing a specific amount of halide ions (bromide ions or iodide ions) is formed are used. In addition, a step of applying the first ink to the recording medium and a step of recording an image on the recording medium by applying the second ink so that the second ink at least partially overlaps with the area to which the first ink is applied are performed. The recording apparatus of the present invention includes a unit that records an image on a recording medium by applying a second ink after applying the first ink to the recording medium such that the second ink at least partially overlaps with an area to which the first ink is applied.

The recording method of the present invention may be an inkjet recording method using an inkjet recording apparatus equipped with an inkjet recording head. In other words, the first ink and the second ink may be ejected from the inkjet recording head and applied to the recording medium. Examples of the inkjet system include a system that applies mechanical energy to ink and a system that applies thermal energy to ink. In the present invention, a system of applying thermal energy to ink to eject ink may be employed.

In the recording method of the present invention, it is not necessary to perform a step of applying active energy rays such as UV rays or electron beams. Further, in the recording method of the present invention, a treatment liquid containing a functional material or the like may be applied to the recording medium before the first ink and the second ink. However, as long as the above-described recording medium is used, it is generally not necessary to perform the step of applying the treatment liquid different from the first ink and the second ink. Therefore, at least the first ink may be applied to the recording medium in a dry state (a state in which water is not substantially contained) instead of in a wet state (a state in which water is substantially contained) generated by applying a different aqueous treatment liquid in advance.

Fig. 1A is a schematic perspective view of a relevant part of an example of an inkjet recording apparatus used in the inkjet recording method of the present invention and fig. 1B is a perspective view of a head cartridge. The inkjet recording apparatus includes a conveying unit (not shown) that conveys the recording medium 32, and a carriage shaft 34. The head cartridge 36 may be mounted to the carriage shaft 34. The head cartridge 36 is equipped with recording heads 38 and 40 and is configured to match an ink cartridge 42. While the head cartridge 36 is conveyed in the main scanning direction along the carriage shaft 34, ink (not shown) is ejected from the recording heads 38 and 40 toward the recording medium 32. As the recording medium 32 is conveyed in the sub-scanning direction by a conveying unit (not shown), an image is recorded on the recording medium 32.

First ink

The first ink is an aqueous ink containing silver particles. The first ink may be for jetting ink. However, since the first ink does not necessarily need to be an active energy ray-curable type, it is not necessary to contain a monomer having a polymerizable group or the like.

The components constituting the first ink are described below.

Silver particles

The silver particles are composed of silver atoms. The silver particles may contain other metal atoms, oxygen atoms, sulfur atoms, carbon atoms, and the like in addition to the silver atoms. The proportion (%) of silver atoms in the silver particles may be 50.0 mass% or more. The content (mass%) of the silver particles in the first ink may be 2.0 mass% or more and 15.0 mass% or less with respect to the total mass of the ink.

The cumulative 50% particle diameter on a volume basis of the silver particles measured by the dynamic light scattering method is preferably 200nm or less and more preferably 150nm or less. The cumulative 50% particle diameter on a volume basis of the silver particles means a particle diameter at which a cumulative volume from the small particle diameter side in a particle diameter cumulative curve reaches 50% with respect to the total volume of the silver particles. When the cumulative 50% particle diameter is small, the proportion of silver atoms present in the surface of the silver particle increases relative to the total number of silver atoms per unit mass, and this means that there are many silver atoms that can easily move in the silver particle. When the proportion of silver atoms capable of easily moving in the silver particles is increased, the silver atoms present in the surface of a certain silver particle can easily form metallic bonds with the silver atoms present in the surfaces of the surrounding silver particles, whereby the fusion of the silver particles easily occurs. As a result, the coloring material is likely to remain on the silver layer, whereby the color developability of the image tends to be improved. The cumulative 50% particle diameter is preferably 1nm or more and more preferably 10nm or more.

The volume-based cumulative 50% particle diameter of the silver particles is measured as follows by using a sample prepared by diluting the first ink or the dispersion of the silver particles with water. After the sample was applied to the substrate formed of the silicone material, water was removed to prepare the sample. By using the obtained sample, 3,000 or more silver particles are observed with a Scanning Electron Microscope (SEM), a Transmission Electron Microscope (TEM), or the like and image processing is performed to calculate the particle diameter having the above definition. In the following examples, after observing the silver particles, the particle diameter was calculated by using an image analyzer/measurement software (trade name: "WinROOF2015", manufactured by Mitani corporation). The particle diameter of the silver particles can be measured by a dynamic light scattering method using an ink or a dispersion; however, since the measured value tends to fluctuate due to the influence of fusion or the like, the measurement can be performed on the above-described sample diluted with water.

Examples of the production method of silver particles include a method involving pulverizing a silver lump with a pulverizer such as a ball mill or a jet mill (pulverization method) and a method involving aggregating silver ions or silver complexes by reduction using a general reducing agent (reduction method). In the present invention, from the viewpoint of controlling the particle diameter of the silver particles and the dispersion stability of the silver particles, silver particles produced by a reduction method may be used.

The silver particles may be dispersed and used by using a surfactant or a dispersant such as a resin. The content (% by mass) of the dispersant in the aqueous ink may be 0.1% by mass or more and 5.0% by mass or less with respect to the total mass of the ink. The mass ratio of the content (mass%) of the dispersant to the content (mass%) of the silver particles in the aqueous ink may be 0.2 times or more and 1.5 times or less.

Examples of the dispersant for silver particles include various surfactants such as anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Examples of the anionic surfactant include fatty acid salts, alkyl sulfate ester salts, alkylaryl sulfonates, alkyldiaryl ether disulfonates, dialkyl sulfosuccinates, alkyl phosphates, naphthalene sulfonate formaldehyde condensates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phosphate ester salts, and fatty acid esters of glycerol boric acid. Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene oxypropylene block copolymers, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene alkylamines, fluorine-based compounds, and silicon-based compounds. Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, alkylpyridinium salts, and alkylimidazolium salts. Examples of amphoteric surfactants include alkylamine oxides and phosphatidylcholine.

A resin containing a unit having an anionic group and a unit having no anionic group can be used as a dispersant for the silver particles. Examples of the resin skeleton include vinyl-based resins, ester-based resins, amino-based resins, acrylic-based resins, epoxy-based resins, urethane-based resins, ether-based resins, amide-based resins, phenolic-based resins, silicone-based resins, and fluorine-based resins.

Aqueous medium

The first ink is an aqueous ink containing at least water as an aqueous medium. The first ink may contain water or an aqueous medium as a mixed medium containing water and a water-soluble organic solvent. The water may be deionized water or ion-exchanged water. The water content (% by mass) in the first ink may be 50.0% by mass or more and 95.0% by mass or less with respect to the total mass of the ink. The water-soluble organic solvent may be any as long as it is water-soluble, and alcohols, (poly) alkylene glycols, glycol ethers, nitrogen-containing polar solvents, sulfur-containing polar solvents, and the like can be used. The content (% by mass) of the water-soluble organic solvent in the first ink may be 3.0% by mass or more and 50.0% by mass or less with respect to the total mass of the ink. When the first ink is used in the inkjet recording method and the water-soluble organic solvent content is outside the above range, reliability such as sticking resistance and ejection stability is significantly reduced.

Surface active agent

The first ink may further contain other surfactants in addition to the surfactant that can be used as a dispersant for the silver particles. In the first ink, the content (mass%) of a surfactant other than the surfactant serving as the dispersant for the silver particles may be 0.1 mass% or more and 2.0 mass% or less with respect to the total mass of the ink. Examples of the surfactant include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Among them, nonionic surfactants such as ethylene oxide adducts of acetylene glycol or polyoxyethylene alkyl ethers are preferable.

Other additives

The first ink may contain, in addition to the above components, a water-soluble organic compound which is solid at 25 ℃, such as urea or a derivative thereof, trimethylolpropane, or trimethylolethane. Further, the first ink may contain various additives such as an antifoaming agent, a pH adjusting agent, a rust inhibitor, an antiseptic, an antifungal agent, an antioxidant, a reduction inhibitor, and a chelating agent, as necessary, in addition to the above components.

Physical properties of ink

The viscosity (mPa · s) of the first ink at 25 ℃ is preferably 1mPa · s or more and 6mPa · s or less and more preferably 1mPa · s or more and 4mPa · s or less. The surface tension (mN/m) of the first ink at 25 ℃ is preferably 10mN/m or more and 60mN/m or less, more preferably 20mN/m or more and 50mN/m or less and still more preferably 25mN/m or more and 40mN/m or less.

Second ink

The second ink is an aqueous ink containing a coloring material. The second ink may be for jetting ink. However, since the second ink does not necessarily have to be an active energy ray-curable type, it is not necessary to contain a monomer having a polymerizable group or the like. The components constituting the second ink are described below.

Coloring material

Examples of the coloring material include dyes and pigments. The coloring material content (% by mass) in the second ink is preferably 1.0% by mass or more and 10.0% by mass or less and more preferably 2.0% by mass or more and 8.0% by mass or less with respect to the total mass of the ink.

The dye may be an anionic dye. The dye may be a compound having at least one skeleton selected from the group consisting of an azo skeleton, a phthalocyanine skeleton, an anthrapyridone skeleton, and a xanthene skeleton. Examples of the pigment include inorganic pigments such as carbon black and titanium oxide; and organic pigments such as azo, phthalocyanine, quinacridone, isoindolinone, imidazolone, diketopyrrolopyrrole and dioxazine. Examples of the pigment dispersion system include resin-dispersed pigments using a resin as a dispersant and self-dispersed pigments in which a hydrophilic group is bonded to the particle surface of the pigment. For example, a resin-bonded pigment in which a resin is chemically bonded to the particle surface of the pigment or a microcapsule pigment in which the particle surface of the pigment is covered with a resin or the like may be used. The coloring material may be a dye or a resin-dispersed pigment using a resin dispersant.

Aqueous medium

The second ink is an aqueous ink containing at least water as an aqueous medium. The second ink may contain water or an aqueous medium as a mixed medium containing water and a water-soluble organic solvent. The water may be deionized water or ion-exchanged water. The water content (% by mass) in the second ink may be 50.0% by mass or more and 95.0% by mass or less with respect to the total mass of the ink. The water-soluble organic solvent may be any as long as it is water-soluble, and alcohols, (poly) alkylene glycols, glycol ethers, nitrogen-containing polar solvents, sulfur-containing polar solvents, and the like can be used. The content (% by mass) of the water-soluble organic solvent in the second ink may be 3.0% by mass or more and 50.0% by mass or less with respect to the total mass of the ink. When the second ink is used in the inkjet recording method and the water-soluble organic solvent content is outside the above range, reliability such as sticking resistance and ejection stability is significantly reduced.

Other Components

The second ink may contain, in addition to the above components, a water-soluble organic compound which is solid at 25 ℃, such as urea or a derivative thereof, trimethylolpropane, or trimethylolethane. Further, the second ink may contain various additives such as a surfactant, an antifoaming agent, a pH adjuster, a rust inhibitor, an antiseptic, an antifungal agent, an antioxidant, a reduction inhibitor, and a chelating agent, as necessary, in addition to the above components.

Physical properties of ink

The viscosity (mPa · s) of the second ink at 25 ℃ is preferably 1mPa · s or more and 6mPa · s or less and more preferably 1mPa · s or more and 4mPa · s or less. The surface tension (mN/m) of the second ink at 25 ℃ is preferably 10mN/m or more and 60mN/m or less, more preferably 20mN/m or more and 50mN/m or less, and still more preferably 25mN/m or more and 40mN/m or less.

Recording medium

The recording medium has an ink-receiving layer containing a specific halide ion. The ink-receiving layer is typically disposed on a substrate. The structure of the recording medium is described below.

Base material

The substrate may be any article having an ink-receiving layer formed on at least one surface thereof, and an example of the substrate is paper. Specific examples of the paper include synthetic paper formed of resin or the like and paper formed of pulp. Paper obtained from wood pulp as a main raw material and by adding synthetic pulp such as polypropylene or synthetic fiber such as nylon or polyester as necessary is one example of paper. Examples of wood pulp include hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP). The pulp may be a chlorine-free pulp such as a chlorine-free bleached pulp (elemental chlorine-free (ECF) and totally chlorine-free (TCF)). The thickness (μm) of the base material may be 50 μm or more and 400 μm or less.

A resin layer may be formed on the substrate. The resin layer may be formed on only one surface of the substrate or on both surfaces of the substrate. Examples of the resin forming the resin layer include thermoplastic resins such as acrylic resins, acryl silicone resins, olefin resins, or styrene-butadiene copolymers, among which olefin resins are preferable. Examples of the olefin-based resin include polyethylene, polypropylene, and polyisobutylene, with polyethylene being preferred. The polyethylene may be Low Density Polyethylene (LDPE) or High Density Polyethylene (HDPE). To adjust opacity, whiteness, and color, etc., additives such as white pigments, fluorescent whitening agents, and ultramarine may be added to the resin forming the resin layer. To increase the opacity, a white pigment such as titanium oxide may be included. The content (mass%) of the white pigment in the resin layer may be more than 0.0 mass% and 25.0 mass% or less with respect to the total mass of the resin layer.

Ink receiving layer

Ink receiving layer requiring packContaining a halide ion selected from the group consisting of bromide ion and iodide ion and desirably having a concentration of 0.1mmol/m²Above and 0.8mmol/m²The following halide ion content. One layer or two or more layers of ink-receiving layer may be provided, and when there are two or more layers of ink-receiving layer, the ink-receiving layer farthest from the substrate has the above-described structure. The ink-receiving layer may be formed on only one surface of the substrate or on both surfaces of the substrate.

An example of a technique for causing the ink-receiving layer to contain a halide ion selected from the group consisting of bromide ions and iodide ions is a technique involving the use of a water-soluble metal halide. Specifically, a bromide or iodide of an alkali metal or alkaline earth metal may be used. Examples of alkali metals include lithium, sodium and potassium and examples of alkaline earth metals include magnesium and calcium. Alkali metal bromides or iodides may be used because of their better solubility in water. Although the effect of the present invention can be obtained from both bromide ion and iodide ion, bromide ion is preferable from the viewpoint of the whiteness of the ink-receiving layer.

Content (mmol/m) of halide ion selected from the group consisting of bromide ion and iodide ion in the ink-receiving layer²) Is 0.1mmol/m²Above and 0.8mmol/m²The following. The content may be 0.3mmol/m²Above and 0.7mmol/m²The following. In the present invention, the ink-receiving layer may not contain chloride ions. When chloride ion is used, the chloride ion content (mmol/m) in the ink-receiving layer is from the viewpoint of suppressing a decrease in gloss after storage²) Preferably 0.5mmol/m²Less and more preferably 0.1mmol/m²The following. Particularly preferably, the ink-receiving layer does not contain chloride ions.

The halide ion content in the ink-receiving layer can be determined by ion chromatography. Specifically, 10mL of ion-exchanged water was put into a 20mL vial (diameter: 16mm) and the cap was closed so that the ink-receiving layer side of the recording medium was in contact with the contents of the vial and the vial was fixed so that the ion-exchanged water did not leak. Subsequently, the vial was inverted and left to stand at 25 ℃ for 24 hours. In this way, the ink-receiving layer is brought into contact with water and halide ions are extracted. The obtained extract was used to quantitatively analyze anions by ion chromatography, thereby finding the halide ion content in the ink-receiving layer. In the present specification, the halide ion content is represented by millimoles per unit area of the ink-receiving layer.

Cationic resin

Unlike a pigment having a particle diameter and being in a dispersed state in ink, a dye in ink is in a dissolved state. Therefore, it is difficult to leave the dye on the silver layer, and the color developability tends to be relatively low, as compared with the pigment. When an anionic dye is used as the coloring material in the second ink, an ink-receiving layer containing a cationic resin may be used. When the second ink is applied to the silver layer formed on the recording medium, at least a portion of the cationic resin in the ink-receiving layer is dissolved in the liquid component of the second ink. A part of the dissolved cationic resin passes through the pores in the silver layer and oozes out on or near the surface of the silver layer (the surface to which the second ink is applied). The leached cationic resin reacts with the anionic group of the dye, and this causes the dye to be easily precipitated and leaves the dye on the silver layer; therefore, even when a dye is used, the decrease in color developability of an image can be effectively suppressed.

Examples of the cationic resin are resins having an amine structure and the like, and the resin may be in the form of a salt. The amine may be any primary to quaternary amine. The cationic resin may be a resin having a nitrate-type or sulfate-type amine structure. Examples of the nitrate of the resin having an amine structure include polyallylamine nitrate and dicyandiamide/diethylenetriamine resin nitrate. Examples of the sulfate of the resin having an amine structure include polyallylamine sulfate and dicyandiamide/diethylenetriamine resin sulfate. The weight average molecular weight of the cationic resin may be 1,000 or more and 100,000 or less. The amine value of the cationic resin may be 50mgKOH/g or more and 300mgKOH/g or less.

Cationic resin content (g/m) in ink-receiving layer²) May be 0.2g/m²Above and 5.0g/m²The following. When it containsThe amount is less than 0.2g/m²In the case where the amount of the cationic resin is too small, precipitation of the dye cannot easily occur; therefore, an effect of suppressing a decrease in color rendering of an image is not sufficiently obtained. When the content is more than 5.0g/m²When the amount of the cationic resin is too large and the ink absorbency of the ink-receiving layer tends to decrease, the liquid component of the ink remains in the ink-receiving layer and the precipitation of the dye in the ink cannot occur smoothly. As a result, the dye hardly remains on the silver layer and the effect of suppressing the decrease in color developability of the image is not sufficiently obtained. Cationic resin content (g/m) in ink-receiving layer²) More preferably 0.6g/m²Above and 3.0g/m²The following.

Rust inhibitor and antioxidant

The ink-receiving layer may contain at least one of a rust inhibitor and an antioxidant. When the ink-receiving layer contains a rust inhibitor or an antioxidant, ionization of silver particles by an oxidizing gas such as nitrogen oxide or light can be suppressed. As a result, silver halide is hardly formed and reduction in glossiness after storing the image can be more effectively suppressed.

The rust inhibitor may be 1,2, 3-benzotriazole or a derivative thereof. Derivatives of 1,2, 3-benzotriazole include 1- (methoxymethyl) -1H-benzotriazole and 1- (hydroxymethyl) -1H-benzotriazole. Content (g/m) of rust inhibitor in ink-receiving layer²) May be 0.02g/m²Above and 0.15g/m²The following.

The antioxidant may be ascorbic acid or a salt thereof. Examples of cations forming salts of ascorbic acid include ions of alkali metals such as lithium, sodium and potassium, and ions of alkaline earth metals such as magnesium and calcium. Antioxidant content (g/m) in ink-receiving layer²) May be 0.05g/m²Above and 0.25g/m²The following.

Inorganic particles

The ink-receiving layer may contain inorganic particles. Examples of the inorganic particles include alumina hydrate, alumina, silica, colloidal silica and titanium dioxide. The inorganic particles may be alumina hydrate, alumina, or silica because a porous structure having high ink absorbency may be formed. Alumina hydrate, alumina and silica may be used in combination. The inorganic particle content (% by mass) in the ink-receiving layer is preferably 50.0% by mass or more and 98.0% by mass or less and more preferably 70.0% by mass or more and 96.0% by mass or less with respect to the total mass of the ink-receiving layer.

Examples of the alumina include gas-phase aluminas such as γ -alumina, α -alumina, δ -alumina, θ -alumina, and χ -alumina, among which γ -alumina is preferable from the viewpoint of optical density of an image and ink absorbency.

The alumina hydrate and the alumina can be dispersed so as to be in a dispersed state in a coating liquid for forming an ink-receiving layer (hereinafter, may be referred to as "first coating liquid") by using a dispersant. The dispersant may be an acid, and particularly, from the viewpoint of suppressing image blur (image blur), may be R-SO₃And H represents a compound. In the formula, R represents a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, or an alkenyl group having 2 or more and 4 or less carbon atoms. R may be substituted with an oxo group, a halogen atom, an alkoxy group or an acyl group. A specific example of the above compound is methanesulfonic acid. The acid content is preferably 1.0% by mass or more and 2.0% by mass or less and more preferably 1.3% by mass or more and 1.6% by mass or less with respect to the alumina hydrate or alumina content.

Silica is roughly classified into those formed by a wet method and those formed by a dry method (vapor phase method). The wet process involves generating active silica by acid decomposition of silicate, polymerizing the active silica to an appropriate degree, and causing sedimentation to obtain "hydrous silica". The dry process (vapor phase process) relates to obtaining "anhydrous silica" by a process involving high-temperature vapor phase hydrolysis of silicon halide (flame hydrolysis process) or a process involving heating, reducing and evaporating silica sand and coke using an electric arc in an electric furnace to perform oxidation with air (arc process). Among them, fumed silica obtained by a dry process (vapor phase process) is preferably used. Fumed silica has a large specific surface area and excellent ink absorbency and a low refractive index, and can form a transparent ink-receiving layer; therefore, fumed silica is preferable from the viewpoint of color developability of an image.

The average primary particle diameter of the inorganic particles is preferably 150nm or less, more preferably 1nm or more and 100nm or less, and still more preferably 3nm or more and 30nm or less. The average primary particle diameter of the inorganic particles is a number average particle diameter measured from the diameter of a circle having the same area as the projected area of the primary particles of the inorganic particles when observed with an electron microscope. The measurement was performed on more than 100 particles.

As described above, the inorganic particles may be dispersed in the first coating liquid by a dispersant and used. The average secondary particle diameter of the inorganic particles in the first coating liquid is preferably 1nm or more and 500nm or less, more preferably 1nm or more and 300nm or less and still more preferably 10nm or more and 250nm or less. The average secondary particle diameter of the inorganic particles is a cumulative 50% particle diameter on a volume basis measured by a dynamic light scattering method.

Coating amount (g/m) of inorganic particles applied to substrate when forming ink-receiving layer²) Can be 8g/m²Above and 45g/m²The following. Within this range, the ink-receiving layer is likely to have a desired thickness. The coating amount of the inorganic particles can be adjusted by the content of the inorganic particles in the first coating liquid and the coating amount of the first coating liquid.

Binder

The ink-receiving layer may contain a binder that binds the inorganic particles and forms a film. Examples of the binder include polymers cationized by using a cationic group; a polymer having a surface cationized by using a cationic surfactant; a polymer obtained by polymerizing monomers constituting the polymer in the presence of a cationic polyvinyl alcohol such that the polyvinyl alcohol is distributed on the surface of the polymer; a polymer obtained by polymerizing monomers constituting the polymer in a suspension dispersion of cationic colloidal particles so that the cationic colloidal particles are distributed on the surface of the polymer; aqueous binders such as thermosetting synthetic resins such as melamine resins or urea resins; and synthetic resins such as polymers or copolymers of acrylic esters or methacrylic esters, for example, polymethyl methacrylate.

Among the above binders, polyvinyl alcohol or a derivative thereof (hereinafter, may be referred to as "polyvinyl alcohol compound") capable of forming a transparent film is preferably used. Examples of the derivative of polyvinyl alcohol include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, and polyvinyl acetal.

From the viewpoint of ink absorbency, the mass ratio of the binder content (mass%) to the inorganic particle content (mass%) in the ink-receiving layer is preferably 0.50 times or less and more preferably 0.30 times or less. The above mass ratio is preferably 0.05 times or more and more preferably 0.08 times or more from the viewpoint of the binding ability of the inorganic particles.

When the first coating liquid is prepared, the polyvinyl alcohol-based compound may be used as an aqueous solution. The content (solid content, mass%) of the polyvinyl alcohol compound in the first coating liquid may be 3.0 mass% or more and 20.0 mass% or less with respect to the total mass of the first coating liquid.

Crosslinking agent

The ink-receiving layer may contain a crosslinking agent to improve water resistance. Examples of the crosslinking agent include zirconium-based compounds, amide-based compounds, aluminum-based compounds, and boric acids. In particular, when a polyvinyl alcohol-based compound is used as the binder, boric acids may be used. Since the polyvinyl alcohol-based compound has many hydroxyl groups and is highly hydrophilic, the hydroxyl groups react with water in the ink, and the ink-receiving layer is likely to swell. As a result, the ink absorbency of the ink-receiving layer tends to decrease. Even when the polyvinyl alcohol-based compound is contained in the ink-receiving layer, the presence of the crosslinking agent causes the hydroxyl group to selectively react with the crosslinking agent; therefore, swelling of the ink-receiving layer is suppressed, and a decrease in ink absorbency can be suppressed.

Examples of boric acids include orthoboric acid (H)₃BO₃) Metaboric acid and diboronic acid. The boronic acids may be in the form of salts and may be water soluble salts. Examples include alkali metal salts of boric acid such as sodium or potassium salts; alkaline earth metal salts of boric acid such as magnesium or calcium salts;and ammonium salts of boric acid. From the viewpoints of the stability with time of the first coating liquid and the suppression of cracks, orthoboric acid may be used.

When the ink-receiving layer contains a polyvinyl alcohol-based compound and a crosslinking agent, theoretically, the following condition can be satisfied assuming that the amount of the crosslinking agent that can react with the hydroxyl group of the polyvinyl alcohol-based compound without excess or deficiency is 1.00 equivalent. The content of the crosslinking agent in the ink-receiving layer may be 0.10 equivalent or more and 1.20 equivalent or less with respect to the content of the polyvinyl alcohol-based compound. Within this range, the reaction between the polyvinyl alcohol-based compound and the crosslinking agent proceeds sufficiently, and therefore the color developability and glossiness of the image can be improved in a well-balanced manner. The amount of the crosslinking agent to be used may be appropriately adjusted depending on production conditions and the like. The content of the crosslinking agent relative to the content of the binder in the ink-receiving layer is preferably 1.0% by mass or more and 50.0% by mass or less and more preferably 5.0% by mass or more and 40.0% by mass or less.

Other Components

The ink-receiving layer may contain, in addition to the above components, various additives such as a pH adjuster, a thickener, a mold release agent, a fluorescent brightener, an ultraviolet absorber, a preservative, an antifungal agent, a water resistant agent, and a curing agent, as needed.

pH of paper surface

The paper surface pH of the recording medium may be 6.0 or less. The paper surface pH of the recording medium is the pH of the ink-receiving layer, and may be in accordance with JAPAN TAPPI No.49-1 "paper and paperboard-surface pH test method-part 1: measured by the Glass Electrode Method (paper Board-Surface pH Testing Method-Part 1: Glass Electrode Method) ".

Method for producing recording medium

The recording medium used in the present invention can be produced by any method as long as the method is capable of forming an ink-receiving layer containing a specific halide ion in an amount within a specific range. Specifically, the following methods (i) and (ii) can be used to produce the recording medium. Here, a case where a metal halide is used as a compound that can generate a specific halide ion is described as an example. The rust inhibitor and the antioxidant may be contained in either one of the first coating liquid and the second coating liquid.

(i) To a method of applying a first coating liquid containing a metal halide, inorganic particles, or the like to a substrate.

(ii) To a method of applying a first coating liquid containing inorganic particles or the like to a substrate and then applying another second coating liquid containing a metal halide or the like to the substrate.

Method (i) involves forming the ink-receiving layer by a single application step. According to the method (ii), after the porous layer is formed by applying the first coating liquid, the second coating liquid is applied so that a specific halide ion is present in the porous layer to form the ink-receiving layer. When the method (ii) is used, the first coating liquid may be dried as needed after the first coating liquid is applied to the substrate and before the second coating liquid is applied. Which of these methods is adopted can be determined according to the kind of production equipment, productivity, and the like.

The coating liquid may be applied to the substrate by using a curtain coater, an extrusion system coater, a slide hopper system coater, or the like. During application, the coating liquid may be heated. Examples of the drying method include a method using a hot air dryer such as a straight tunnel dryer, an arch dryer, an air circulation dryer, or a sinusoidal air floating dryer, and a method using a dryer using infrared rays, a heating dryer, microwaves, or the like.

Recorded matter

The recorded matter of the present invention includes an ink-receiving layer, a first layer adjacent to the ink-receiving layer, and a second layer adjacent to the first layer. The ink-receiving layer contains a halide ion selected from the group consisting of bromide ion and iodide ion and has a concentration of 0.1mmol/m²Above and 0.8mmol/m²The halide ion content (mmol/m) of²). The first layer is formed of silver and the second layer is formed of a coloring material. A recorded matter having such a structure can be prepared by the recording method of the present invention described above. As described above, the recorded matter of the present invention has excellent color developability and excellent glossiness even after storage.

Examples

The present invention will now be described in further detail by the following examples and comparative examples; however, these examples do not limit the present invention without departing from the gist of the present invention. "parts" and "%" indicating amounts of components are based on mass unless otherwise specified.

Preparation of silver particle dispersion

Silver particle dispersions 1 to 3 were prepared by referring to the description of example 2 in PCT Japanese translation patent publication No. 2010-507727. During the preparation, the particle size was adjusted by adjusting the stirring speed. The silver particle content in each dispersion was 20.0% and the resin content was 2.0%. The cumulative 50% particle diameter on a volume basis of the silver particles was 32nm in dispersion 1, 150nm in dispersion 2 and 160nm in dispersion 3. The cumulative 50% particle size on a volume basis of the silver particles was measured by the following procedure. First, a dispersion diluted about 2,000 times (on a mass basis) with ion-exchanged water was applied to a substrate formed of a silicone material, and water was removed by drying to prepare a sample. Next, by using the obtained sample, 3,000 or more silver particles were observed with a scanning electron microscope and image analysis was performed with image analysis/measurement software (trade name: "WinorOF 2015", manufactured by MITANI Corporation) to calculate a cumulative 50% particle diameter of the silver particles.

Preparation of the first ink

The components (unit:%) shown in table 1 were mixed, sufficiently stirred, and pressure-filtered with a filter having a pore size of 1.2 μm, and as a result, a first ink was obtained. Acetylenol E100 is a trade name for a nonionic surfactant produced by Kawaken Fine Chemicals Co., Ltd.

TABLE 1 composition of the first ink (unit:%)

Preparation of the pigmented Material

Pigment Dispersion 1

A mixture was obtained by mixing 10.0 parts of a pigment (c.i. pigment red 122), 30.0 parts of an aqueous resin dispersant solution, and 60.0 parts of ion-exchanged water. An aqueous solution having a water-soluble resin content of 10.0% was prepared by neutralizing a styrene-acrylic acid copolymer having an acid value of 120mgKOH/g and a weight average molecular weight of 8,000 with potassium hydroxide in an amount equimolar to the acid value, and then dissolving the neutralized product in ion-exchanged water, and was used as an aqueous solution of a resin dispersant. The obtained mixture and 200 parts of zirconia beads having a diameter of 0.3mm were put into a batch type vertical sand mill (produced by AIMEX co., ltd.) and dispersed under water cooling for 5 hours. Subsequently, coarse particles were removed by centrifugation. The resultant mixture was pressure-filtered with a cellulose acetate filter (manufactured by Advantech co., ltd.) having a pore diameter of 3.0 μm, to thereby prepare a pigment dispersion liquid 1 having a pigment content of 10.0% and a resin dispersant content of 3.0%.

Pigment dispersion liquid 2

A pigment dispersion liquid 2 having a pigment content of 10.0% and a resin dispersant content of 3.0% was prepared by the same procedure except that the pigment was changed to c.i. pigment blue 15: 3.

Pigment Dispersion 3

A pigment dispersion liquid 3 having a pigment content of 10.0% and a resin dispersant content of 3.0% was prepared by the same procedure except that the pigment was changed to c.i. pigment yellow 74.

Dye 1

According to the description of the synthetic method in international publication No.2006/082669, a potassium salt represented by the following formula (1) (dye 1) in the form of a free acid is synthesized.

Preparation of the second ink

The components (unit:%) shown in table 2 were mixed, sufficiently stirred, and pressure-filtered with a filter having a pore size of 1.2 μm, and as a result, a second ink was obtained. Acetylenol E100 is a trade name for a nonionic surfactant produced by Kawaken Fine Chemicals Co., Ltd.

TABLE 2 composition of the second ink (unit:%)

Preparation of the substrate

Substrate 1

To 100.0 parts of broadleaf tree bleached kraft pulp slurry, 20.0 parts of light calcium carbonate was added, and then 2.0 parts of cationic starch and 0.3 parts of alkenyl succinic anhydride-based neutral sizing agent were added thereto and mixed, thereby obtaining a papermaking stock. The obtained papermaking stock was dried by using a fourdrinier machine until the water content was 10% (on a mass basis), to thereby obtain a base paper. A7% aqueous solution of oxidized starch was applied to both surfaces of the base paper obtained by size press so that the total amount of the aqueous solution applied on both surfaces was 4g/m²Then dried until the water content was 7% (by mass), thereby obtaining a basis weight of 110g/m²The base paper of (1). A resin composition composed of 70 parts of high-density polyethylene and 20 parts of low-density polyethylene was applied to both surfaces of the obtained base paper by using a melt extruder so that the coating amount per surface was 30g/m². As a result, the substrate 1 was obtained.

Base material 2

To 100.0 parts of broadleaf tree bleached kraft pulp slurry, 20.0 parts of light calcium carbonate was added, and then 2.0 parts of cationic starch and 0.3 parts of alkenyl succinic anhydride-based neutral sizing agent were added thereto and mixed, thereby obtaining a papermaking stock. The obtained papermaking stock was dried by a fourdrinier machine until the water content was 10% (on a mass basis), to thereby obtain a base paper. A7% aqueous solution of oxidized starch was applied to both surfaces of the obtained base paper by size press so that the total amount of the aqueous solution applied on both surfaces was 4g/m²Then dried until the water content was 7% (by mass), thereby obtaining a basis weight of 200g/m²The base paper of (1). The base paper is used as the base material 2.

Base material 3

Synthetic paper (trade name: "YUPO HIGH GLOSS gas GAR 110", manufactured by yuppoccorportation) formed of polypropylene is used as the base material 3.

First of allPreparation of coating liquid

First, various solutions for preparing the first coating liquid were prepared. An aqueous PVA solution having a polyvinyl alcohol content of 8.0% was prepared by adding polyvinyl alcohol (trade name: "PVA235", produced by KURARAY CO., LTD., degree of polymerization: 3500, degree of saponification: 88%) to ion-exchanged water. Orthoboric acid (crosslinker) was added to the ion-exchanged water to obtain an aqueous orthoboric acid solution having a crosslinker content of 3.0%. Potassium bromide was added to ion-exchanged water, thereby obtaining an aqueous potassium bromide solution having a potassium bromide content of 10.0%. 1,2, 3-benzotriazole was added to ethanol to obtain a BTA solution having a 1,2, 3-benzotriazole content of 10.0%.

First coating liquid 1

Alumina hydrate (trade name: "DISPERSAL HP14", manufactured by Sasol) was added to ion-exchanged water, thereby obtaining a dispersion having an alumina hydrate content of 30.0%. To the dispersion, methanesulfonic acid was added so that the methanesulfonic acid (dispersant of alumina hydrate) content was 1.6% with respect to the alumina hydrate content and the resultant mixture was sufficiently stirred, thereby obtaining a colloidal sol. An appropriate amount of ion-exchanged water was added to the obtained colloidal sol, thereby obtaining a dispersion 1 having an inorganic particle (alumina hydrate) content of 27.0%. An aqueous PVA solution was added to the dispersion 1 obtained as above so that the content of polyvinyl alcohol with respect to the content of inorganic particles was 11.0% and mixed. Next, an aqueous orthoboric acid solution was added so that the orthoboric acid content was 2.0% with respect to the inorganic particle content and mixed. As a result, a first coating liquid 1 was obtained.

First coating liquid 2

The BTA solution was added to the coating solution 1 obtained as above so that the 1,2, 3-benzotriazole content was 0.4% with respect to the inorganic particle content and mixed. Further, an aqueous potassium bromide solution was added so that the potassium bromide content was 0.2% with respect to the inorganic particle content and mixed. As a result, the first coating liquid 2 was obtained.

First coating liquid 3

Wet Silica (trade name: "NIPGEL AY-603", by Tosoh Silica Corporation) was added to ion-exchanged water, thereby obtaining dispersion 2 having a wet Silica content of 15.0%. To the dispersion 1 obtained as above, the dispersion 2 was added so that the mass ratio of alumina hydrate to wet silica was 97.5:2.5, and mixed. As a result, a dispersion liquid 3 having an inorganic particle (alumina hydrate and wet silica) content of 20.0% was obtained. An aqueous PVA solution was added to the dispersion 3 obtained as above so that the content of polyvinyl alcohol was 5.5% with respect to the content of inorganic particles, and mixed. Next, an aqueous orthoboric acid solution was added so that the boric acid content was 1.0% with respect to the inorganic particle content, and mixed. The BTA solution was added so that the content of 1,2, 3-benzotriazole was 0.4% with respect to the content of inorganic particles, and mixed. Further, an aqueous potassium bromide solution was added so that the potassium bromide content was 0.4% with respect to the inorganic particle content, and mixed. As a result, a first coating liquid 3 was obtained.

First coating liquid 4

An aqueous PVA solution was added to the dispersion 1 obtained as above so that the content of polyvinyl alcohol was 9.5% with respect to the content of inorganic particles, and mixed. Next, an aqueous orthoboric acid solution was added so that the boric acid content was 0.2% with respect to the inorganic particle content, and mixed. The BTA solution was added so that the content of 1,2, 3-benzotriazole was 0.4% with respect to the content of inorganic particles, and mixed. Further, an aqueous potassium bromide solution was added so that the potassium bromide content was 0.3% with respect to the inorganic particle content, and mixed. As a result, the first coating liquid 4 was obtained.

First coating liquid 5

A potassium bromide aqueous solution was added to the coating liquid 1 obtained as above so that the content of potassium bromide was 0.2% with respect to the content of inorganic particles, and mixed. As a result, the first coating liquid 5 was obtained.

First coating liquid 6

The BTA solution was added to the coating solution 1 obtained as above so that the 1,2, 3-benzotriazole content was 0.4% with respect to the inorganic particle content, and mixed. As a result, the first coating liquid 6 was obtained.

Preparation of the second coating liquid

First, nitric acid was added to polyallylamine (trade name: "PAA-01", manufactured by NITTOBO MEDICAL co., ltd.) to adjust the pH of the liquid to about 4.0, and a liquid containing the nitrate salt of polyallylamine was obtained. The components (unit: part) shown in table 3 were mixed to obtain a second coating liquid. The amounts (parts) of components other than "BTA solution" and "ion-exchanged water" shown in Table 3 were used on a solid basis. The BTA solution is the same as that used to prepare the first coating liquid.

TABLE 3 composition of treatment solutions (unit: parts)

Recording medium

The first coating liquid was applied to the substrate so that the thickness after drying was as shown in table 4, and dried at 80 ℃. Subsequently, with respect to the recording media 1 to 20 and 25 to 29, the second coating liquid was further applied so that the dry coating amount was as shown in table 4, and dried at 80 ℃, thereby obtaining recording media. The recording media 21 to 24 are prepared without using the second coating liquid. The paper surface pH of the recording medium measured by the above method was 4.2 in all cases.

TABLE 4 preparation conditions and Properties of the recording Medium

Preparation and evaluation of recorded matter

The ink prepared as above was loaded into an ink cartridge, and the cartridge of the composition shown on the left side of table 5 was put into an ink jet recording apparatus (trade name: "PIXUS MG3630", manufactured by CANON KABUSHIKI KAISHA) equipped with a recording head that ejects ink by thermal energy. In the embodiment, the definition of the recording duty of 100% of the first ink is an image recorded by applying two ink droplets each of about 11.2ng to an 1/600 inch × 1/600 inch unit area. Further, the definition of a recording duty of 100% of the second ink is an image recorded by applying two ink droplets each of about 5.7ng to an 1/600 inch × 1/600 inch unit area. In the present invention, for each item of the evaluation criteria, AAA, AA, A and B are acceptable levels and C is unacceptable level. The evaluation results are shown in table 5.

Color rendering property

Images were recorded on the recording media shown on the left side of table 5 by applying the first ink so that the recording duty was 100% by using the above-described inkjet recording apparatus. Subsequently, three kinds of second inks are each applied so as to overlap with the region (first ink image) to which the first ink has been applied, so that the recording duty is 100%. As a result, a recorded matter on which three solid images were recorded was prepared. The obtained recorded matter was subjected to the following color measurement in SCI (conditions including static reflected light) mode by using an integral sphere type spectrophotometer (trade name: "CM-2600d", manufactured by Konica Minolta Japan, Inc.). The following chroma (a)^*And b^*) Is L defined by the International Commission on illumination (CIE)^*a^*b^*The value of the system. First, the chromaticity of an image of a portion recorded only by the first ink is measured (a)₀ ^*And b₀ ^*). In addition, the chroma (a) of the image of the portion recorded by both the first ink and the second ink was measured in the same manner₁ ^*And b₁ ^*). Color difference Δ E_abBy the formula Δ E_ab＝{(a₁ ^*-a₀ ^*)²+(b₁ ^*-b₀ ^*)²}^1/2Was calculated and the color rendering was evaluated according to the following evaluation criteria. Delta E_abIs an index representing "deviation" of the color tone of an image recorded by the first ink and the second ink from the color tone of an image recorded with the first ink as a reference. Thus, Δ E_abA high value of (b) means that the hue of the coloring material used in the second ink is easily recognized from the image. Under these evaluation conditions, it is considered that Δ E_abThe image of 2.0 or more is an image in which a hue of the coloring material used in the second ink is recognizable with the naked eye instead of a hue of the silver particles (silver color).

AAA: for all three types of second ink, Δ E_abIs 6.0 or more and less than 10.0.

AA: of the three types of second ink, two types are producedDelta E of 6.0 or more and less than 10.0_abAnd one type produces a Δ E of 2.0 or more and less than 6.0_ab。

A: of the three types of second ink, two types generate Δ E of 6.0 or more and less than 10.0_abAnd one type produces a Δ E of less than 2.0_ab。

B: of the three types of second ink, two types generate Δ E of 2.0 or more and less than 6.0_abAnd one type produces a Δ E of less than 2.0_ab。

C: for all three types of second ink, Δ E_abLess than 2.0.

Suppression of reduction of gloss

A solid image having a recording duty of 100% was recorded by applying the first ink to the recording medium shown on the left side of table 5 by using the above-described inkjet recording apparatus. The solid image was left to stand at 25 ℃ and 50% RH for 1 day, and then the 20 ℃ gloss G of the solid image was measured₁Measured by a gloss meter (trade name: "VG-7000", manufactured by NIPPON DENSHOKU INDUSTRIES Co., LTD). The solid images were then placed in a gas corrosion tester (Suga Test Instruments co., Ltd.) and exposed to the mixed gases at an indoor temperature of 25 ℃ and a relative humidity of 80% for 36 hours. 0.90ppmNO₂Gas, 0.05ppm SO₂Gas and 0.15ppmO₃A mixture of gases is used as the mixed gas. 20 ° gloss G was measured on the exposed solid image in the same manner₂. The remaining gloss ratio was calculated by the following formula and the gloss of the image was evaluated: residual gloss ratio G₂/G₁×100(％)。

AA: the residual gloss ratio is 75% or more.

A: the residual gloss ratio is 60% or more and less than 75%.

B: the residual gloss ratio is 50% or more and less than 60%.

C: the residual gloss ratio was less than 50%.

Table 5: evaluation results

According to the present invention, a recording method and a recording apparatus with which a color metallic image having excellent color developability and excellent glossiness even after the image is stored can be recorded can be provided. According to another aspect of the present invention, a color metal recorded matter having excellent color developability and excellent glossiness even after the image is stored can be provided.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A recording method, characterized in that it comprises:

a step of applying a first ink to a recording medium; and

a step of recording an image on the recording medium by applying a second ink so that the second ink at least partially overlaps with an area to which the first ink is applied,

wherein the first ink is an aqueous ink containing silver particles,

the second ink is an aqueous ink containing a coloring material,

the recording medium has an ink-receiving layer containing a halide ion selected from the group consisting of bromide ion and iodide ion, and

the content of the halide ion of the ink-receiving layer is in mmol/m²Calculated as 0.1mmol/m²Above and 0.8mmol/m²The following.

2. The recording method according to claim 1, wherein the ink-receiving layer contains at least one of a rust inhibitor and an antioxidant.

3. The recording method according to claim 2, wherein the rust inhibitor is 1,2, 3-benzotriazole or a derivative thereof, and the antioxidant is ascorbic acid or a salt thereof.

4. The recording method according to claim 1, wherein the ink-receiving layer contains a rust inhibitor.

5. The recording method according to claim 1, wherein the ink-receiving layer contains a cationic resin.

6. The recording method as claimed in claim 5, wherein the cationic resin is a resin having an amine structure.

7. The recording method according to claim 5, wherein the content of the cationic resin of the ink receiving layer is in g/m²Calculated as 0.2g/m²Above and 5.0g/m²The following.

8. The recording method as claimed in claim 1, wherein the silver particles have a cumulative 50% particle diameter on a volume basis of 150nm or less in nm.

9. The recording method according to claim 1, wherein the first ink and the second ink are applied to the recording medium by ejecting the first ink and the second ink from an inkjet recording head.

10. A recording apparatus, characterized in that it comprises:

a unit configured to record an image on a recording medium by applying a second ink so that the second ink at least partially overlaps with an area to which the first ink is applied, after the first ink is applied to the recording medium,

wherein the first ink is an aqueous ink containing silver particles,

the second ink is an aqueous ink containing a coloring material,

the content of the halide ion of the ink-receiving layerIn mmol/m²Calculated as 0.1mmol/m²Above and 0.8mmol/m²The following.

11. The recording apparatus according to claim 10, wherein the unit configured to apply the first ink and the second ink to the recording medium is an inkjet recording head.

12. A record, characterized in that it comprises:

an ink-receiving layer;

a first layer adjacent to the ink-receiving layer; and

a second layer adjacent to the first layer,

wherein the ink-receiving layer contains a halide ion selected from the group consisting of a bromide ion and an iodide ion,

the content of the halide ion of the ink-receiving layer is in mmol/m²Calculated as 0.1mmol/m²Above and 0.8mmol/m²In the following, the following description is given,

the first layer is formed of silver, and

the second layer is formed of a coloring material.